Registration reset system

ABSTRACT

A programming control system for controlling the processing steps of an electrostatic printing machine of the type employing an endless photoreceptor belt. A sheet position sensitive element in the form of a registration finger is utilized for resetting a complete machine timing cycle for processing operation. This cycle, called pitch is applied to the belt and comprises a predetermined number of electrical pulses some of which control machine events.

United States Patent 91 Donohue [4 1 Feb. 5, 1974 REGISTRATION RESETSYSTEM [75] Inventor: James M. Donohue, Rochester, NY.

[73] Assignee: Xerox Company, Stamford, Conn.

[22] Filed: Aug. 30, 1972 [21] Appl. No.: 284,831

52 U.S.Cl 355/14, 355/16 [51] m. c: G03g 15/00 58 FieldofSearch 355/14,3, 16; 271/53, 57,

[56] References Cited UNITED' STATES PATENTS 3/1970 Maloney et a1.355/14 10/1972 Hickey et a1 355/14 5/1970 Osborne et a1. 355/14 PrimaryExaminerRichard L. Moses [5 7] ABSTRACT A programming control system forcontrolling the processing steps of an electrostatic printing machine ofthe type employing an endless photoreceptor belt. A sheet positionsensitive element in the form of a registration finger is utilized forresetting a complete machine timing cycle for processing operation. Thiscycle, called pitch is applied to the belt and comprises a predeterminednumber of electrical pulses some of which control machine events.

8 Claims, 10 Drawing Figures v PMENTED FEB 51974 'BQTSOQYO v sum 1 OF 5PAIENIEQFEH 51914 397902.)

' sum 3 (1F 5 REGISTRATION RESET SYSTEM This invention relates toelectrostatic printing machines, and in particular, to a uniqueconfiguration of. an endless photoreceptor belt with a sheet positionresponsive element in the form of a plurality of sheet registrationfingers, and the application of a programmed time sequence to theprocessing stations.

Electrostatic printing machines, especially those of the endless belttype employ various processing stations which will uniformly charge,expose, develop, transfer, clean, etc. during any cycle of copying. Forhigh speed operation of these machines, it becomes very important thatthere be a proper base for the timing sequence of operation of theprocessing stations in order to maintain paper registration of all theprocessing functions relative to images. There must be provision for theefficient and assured movement of sheets of copy paper to the transferstation of the machine in timed sequence relative to the production ofelectrostatic latent images, the development thereof, the properorientation of each sheet of the developed image received at thetransfer station, the commencing of energization of all the corotronsused in the machine, the fusing apparatus, and all the sensing elementsutilized for sheet presence monitoring for effective paper jamdetection.

Therefore, the principal object of the present inventionis to improveelectrostatic printing machines, especially those of the type employingelectrostatic photoreceptor belts.

Another object of the present invention is to maintain proper timing ofthe operation of the electrostatic processing stations utilized in themachine so as to effect maximum efficiency in the operation of themachine expecially for high speed reproduction.

The foregoing objects are attained by the timed sequence of operation ofcertain processing stations, based upon the registration of each sheetof paper by registration fingers rotatably mounted on a shaft. Machineprocessing is accomplished by utilizing a pulse generator whichgenerates a continuous train of electrical pulses, some of which areused to initiate operation of the processing components in the machine.The distance of movement of the photoreceptor is directly related tosheet registration during movement thereof, the generation of thepulses, and the resetting of each cycle. Resetting is accomplished foreach sheet of paper and one spacing between it and the next sheet, orthe time between the exposure flashes by the ma chine.

In the United States copending Pat. application, Ser. No. 97,745, filedDec. 14, 1970, in the name of Donohue et al, and assigned to the sameassignee of the present invention, there is described a similarprogramming arrangement wherein the distance of movement of aphotoreceptor belt determines the processing timing sequence. This isaccomplished by having the resetting of control pulses performed by atransfer roller in direct contact with the belt. In the presentinvention, resetting is accomplished by the rotation of a shaftsupporting a plurality of registration fingers for each sheet of paper.By having the distance of sheet travel between the point of registrationand the transfer station precisely factored into the machine processing,the programming of the machine, as in the present invention, is alsobased upon the distance of movement of the belt.

These and other objects will become apparent after reading the followingspecification in conjunction with the drawings wherein:

FIG. 1 is a schematic sectional view of an electrostatic reproductionmachine embodying the principles of the invention;

FIG. 2 is a front elevational view of the drive motor for the machine;

FIG. 3 is a schematic view of the paper supply transports in relation toa sheet registration arrangement;

FIG. 4 is a partial plan view of one of the transports and theregistration arrangement;

FIGS. 5 and 6 are front and side elevational views respectively of aswitching mechanism utilized in sheet registration reset;

FIGS. 7, 8 and 9 are schematic views of the relative positioning ofregistration fingers during various sequences of operation; and

FIG. 10 is an isometric view, partly broken away, of a variable speedimparting device.

For a general understanding of an electrostatic processing system inwhich the invention may be incorporated, reference is had to thedrawings wherein various components of a system are schematicallyillustrated. For purposes of illustration only, the type of printingmachine described for the environment of the present invention is of theelectrostatic type; and particularly one that is based on the process ofxerography. In most electrostatic systems, such as a xerographic machineof the type illustrated, a light image of an original to be reproducedis projected onto the sensitized surface of a xerographic plate to forman electrostatic latent image thereon. For purposes of providing anenvironment for the present invention and therefore, for illustrationpurposes only, the illustrated xerographic system is of the type whereinthe xerographic plate is in the form of an endless belt. In a belt typeenvironment, the present invention is also adapted for integration intoa belt type machine wherein the belt is a conveying element per serather than a form of photoreceptor, and sheets of photoconductivematerial are positioned upon the belt for movement through processingstations. Thereafter, the latent image is developed by means of amagnetic brush developing apparatus to form a xerographic powder image,corresponding to the latent image on the plate surface. The powder imageis then electrostatically transferred to a support surface to which itmay be fixed by a fusing apparatus whereby the powder image is causedpermanently to adhere to the support surface.

The electrostatically attractable developing material commonly used inmagnetic brush developing apparatus comprises a pigmented resinouspowder referred to here as toner" and a carrier of larger granular beadsformed with steel cores coated with a material removed in thetriboelectric series from the toner so that a triboelectric charge isgenerated between the toner powder and the granular carrier. Themagnetizable carrier also provides mechanical control for the formationof brush bristles by virtue of magnetic fields so that the toner can bereadily handled and brought into contact with the exposed xerographicsurface. The toner is then attracted to the electrostatic latent imagefrom the carrier bristles to produce a visible powder image on aninsulating surface.

In the illustrated machine, an original D to be copied is placed upon atransparent support platen P fixedly arranged in an illuminationassembly generally indicated by the reference numeral 10. While upon theplaten, an illumination system comprising two or more lamps andreflectors L are flash energized so as to flash light rays upon theoriginal thereby producing image rays corresponding to the informationalareas on the original. The image rays are projected by means of anoptical system 11 to an exposure station A for exposing thephotosensitive surface of a moving xerographic plate in the form of aflexible photoconductive belt 12. In moving in the direction indicatedby the arrow, prior to reaching the exposure station A, that portion ofthe belt being exposed would have been uniformly charged by a coronadevice 13 located at a belt run extending between belt supportingrollers 14 and 15, the latter being the drive roller for the belt. Theexposure station extends between the roller 14 and a third supportroller 16, and the belt run between these rollers is encompassedentirely by the exposure station for minimizing the space needed for thebelt and its supporting rollers.

The exposure of the belt surface to the light image discharges thephotoconductive layer in the areas struck by light, whereby thereremains on the belt a latent electrostatic image in image configurationcorresponding to the light image projected from the original on thesupporting platen. As the belt surface continues its movement, theelectrostatic image passes around the roller 16 and through a developingstation B located at a third run of the belt and in which there ispositioned a developing apparatus generally indicated by the referencenumeral 17. Suitable means (not shown) such as vacuum panels ortensioning means may be utilized for maintaining the belt flat in any orall three belt runs, and additionally the belt run related to thedevelopment zone B is maintained at an inclined plane. The developingapparatus 17 comprises a plurality of magnetic brushes which carrydeveloping material to the adjacent surface of the upwardly movinginclined photoconductive belt 12 in order to provide development of theelectrostatic image.

The developed electrostatic image is transported by the belt 12 to atransfer station C located at a point of tangency on the belt as itmoves around the drive roller whereat a sheet of copy paper is moved ata speed in synchronism with the moving belt in order to accomplishtransfer of a properly registered developed image. There is provided atthis station a transfer roller 19 which is arranged on the frame of themachine for contacting the non-transfer side of each sheet of copy paperas the same is brought into transfer engagement with the belt 12. Theroller 19 is electrically biased with sufficient voltage so that adeveloped image on the belt 12 may be electrostatically transferred tothe adjacent side of a sheet of paper as the same is brought intocontact therewith.

There is also provided a copy sheet supplying apparatus comprising amain paper feed supply 20 and an auxiliary paper feed supply 21. Each ofthe paper supplies is adapted to separate sheets from their respectivesupply stacks seriatim and to transport the sheets to a sheetregistration station and eventually into contact with the developedimage on the belt as the same is carried around the drive roller 15. Theprogramming or timing control arrangement of the present invention isoperatively associated with each of the paper supply mechanisms 21, 22,the flash illumination devices L for producing an electrostatic latentimage on the belt 12, to

present a developed image at the transfer station C in timed sequencewith the arrival of a sheet of paper, and is coordinated with theactivation of other processing and control devices at the precise timethat these elements are to function for their intended purposes.

After the developed image is transferred to a sheet of paper, it isstripped from the belt 12, and conveyed by a conveying system 23 into afuser apparatus generally indicated by the reference numeral 24 whereinthe developed and transferred xerographic powder image on the sheetmaterial is permanently affixed thereto. After fusing, the finished copyis discharged from the apparatus by conveyor 25 at a suitable point forcollection externally of the apparatus. The remaining toner particlesremaining as residue on the developed images, and those particlesotherwise not transferred are carried by the belt 12 to a cleaningapparatus 26 positioned on the run of the belt between the'rollers 14,15 adjacent the charging device 13. The cleaning device comprises acorotron 27 for neutralizing charges remaining on the particles and arotating brush 28 which operates in conjunction with a vacuum system toremove residual toner particles from the vicinity of the brush.

In order to impart continuous movement to the belt 12, there is provideda drive means 30 comprising a constant speed drive motor and gear boxwhich is directly coupled to the drive roller 15 by a suitable drivechain or timing belt 31 entrained around a sprocket or pulley mounted onthe shaft for the roller 15 and the output shaft 32 for the drive means.The present invention provides a specific arrangement to accomplishpulse generation off of the belt drive motor, and also an entirelydifferent arrangement for periodically resetting the pulse train to zerothereby establishing pitches. To this end, a gear 33 is mounted on thedrive shaft 32 for the drive means 30 and includes a predeterminednumber of teeth 34, each of which becomes aligned with a magnetic pickupelement 35 mounted on the frame of the machine during rotation of thegear. The element 35 is associated with a pulse generating device 36which produces a square wave signal having peaks corresponding to thesuccessive alignments of the teeth 34 with the pick up element 35. Aseach tooth moves adjacent the device 35, the magnetic field in thedevice is set to vary and thereby produce a peak in the signal.

Programming control for the machine processing steps is accomplished inconjunction with pitch reset wherein after a series of electrical pulsesare generated corresponding to the movement of each copy sheet plus onespacing through the transfer station, reset of this number, or pitch, isaccomplished when the photoreceptor belt has travelled a precise,predetermined distance as related to the movement of a copy sheet plusone spacing. Pulse generation for a timing control signal then isaccomplished by utilizing a direct connection of the photoreceptor belt12 to the pulse generating device so as to move at all times directlytherewith as described above and reset is accomplished by a resetmechanism which is reset at a predetermined position of the leading edgeof each sheet of paper in proper registration to a developed image onthe photoreceptor belt. With the belt continuously moving and beingdriven by a drive directly connected to the processing programmingcontrol, each pitch reset occurs precisely at predetermined distances ofmovement of the belt.

The programming control then is acquired by means of a timing devicemechanically coupled to the shaft for the drive means 30 and which isdriven into operation when the roller is rotating. The pulse generatingdevice 36 which is part of the timing apparatus is set to produce acontinuous train of time pulses which can be determined by therotational speed of the drive means 30 and the number of teeth 34 on thegear 33. The. device 36 is electrically connected to a counting device37 which may be in the form of a shift register mechanism which countsthe pulses of the control signal. After a number of pulses have beencounted, the count is restarted or set to zero which is described hereinas the pitch reset. Rather than having a predetermined number of pulsescause the reset, it is preferred to utilize the distance of movement ofthe belt 12 as the reset causing standard. This is accomplished, as willbe described hereinafter, by rotation of sheet registration fingers. Anymachine event or processing step can be initiated; that is, turned Onand Off" or to remain operative for any period of time on any one ormore of the discrete pulses. Pitch reset is accomplished during sheetregistration, after each revolution of registration fingers which arearranged to be periodically interposed in the path of movement of sheetsof paper just immediately prior to the insertion of each sheet into thenip of the transfer roller 19 and the belt 12 at station C.

Operatively associated with the sheet supply is a sheet transportcomprising a plurality of continuously movable belts 40 driven by themain drive by way of rollers 41. Similarly, the sheet supply 21 isassociated with a sheet transport comprising a plurality of belts 42movably driven around rollers 43, by the machine drive 30. The drivingforce for the transports and 42 may be accomplished by means other thanthe machine drive 30, such as by individual motors or a common motor.The transport 42 for the auxiliary paper supply means, when in theoperative mode, transports each sheet fed thereto onto the belts 40 forthe main paper supply 20. In this arrangement, each of the papersupplies is provided with its own sheet transport and one of thetransports directs sheets carried thereby to the other transport so thata single sheet registration mechanism may be employed for cooperationwith each of the sheet supplies.

As shown in FIGS. 3 and 4, sheet registration is accomplished by meansof a plurality of spaced registration fingers 45 mounted on a shaft 46in alignment transversely of the paper sheet path. The shaft is suitablysupported for rotation on the machine frame and is operatively connectedby way of a variable speed device 47 to a drive belt 48 which in turn isoperatively connected to the drive means 30 to be driven at a speedcoordinated with the speed of the belt 12 and the two copy sheettransporting means 40, 42. For each complete rotation of the fingers 45in the direction of the arrow, and when they attain the position shownin FIG. 3, a sheet S is in engagement with the fingers to becomestraightened in its traveling and to become positioned and timed, inother words, registered. The distance between the fingerswhen a sheet isregistered and the nip at station C is arranged to be very small andprecisely known. The instant the fingers become disengaged from eachsheet, the sheets will be in the nip of a pair of driven registrationpinch rollers 50, 51 and these two occurrences are utilized as the pitchreset event. The pulse occurring at that time by the counting mechanism37 is given the designation as the zero pulse. All other pulses arecounted from that event, until the next registration for the next sheetand the corresponding zero pulse. While the occurrence of the leadingedge of the sheet S leaving the fingers 45 being synchronized with theentry of the edge into the nip of the pinch roller has been chosen asthe instant for pitch reset, it is to be understood that otheroccurrences may be utilized for this purpose. For instance, the pitchreset may be made to occur when the fingers 45 are still in engagementwith the leading edge of a sheet and before it reaches the nip of thepinch rollers. What is important, however, is that this precise angularpositioning of the fingers for reset must be utilized for all resetoccurrences. Processing control and steps are set to be actuated orenergized at predetermined pulse counts from a zero pulse, and dependingupon the number of pulses to be generated, say on the order to 1000pulses or so for each sheet registration, it will be appreciated thatvery close and accurate process control can be attained.

The lower registration pinch rollers 51 are mounted for rotation on ashaft 52 between the belts of the belt transport 40 and the fingers 45so as not to impede operation thereof. The shaft 52 is mounted forrotation in a frame (not shown) and is driven by belts 53 and pulleys 54associated with a drive shaft 55 also mounted on the machine frame. Oneof the shafts 55 is driven by way of a belt 56 from a clutch 57associated with the variable speed device 47. In this manner, the pinchrollers 51 are given their rotative drive by the belts 48 from themachine drive motor 30. The upper pinch rollers 50 are idler rollershaving their peripheries in frictional engagement with the lower rollers51 to be rotated therewith.

In order to effect pitch reset at the precise angular positioning of theregistration fingers for each revolution thereof and to permit therecounting of pulses from each zero pulse at sheet registration, aswitching mechanism 58 having a switch associated therewith to beactuated to a controlling position precisely as a sheet is registeredand the fingers are in a predetermined angular position.

The switching mechanism 58 comprises a circular flat housing 59 havingtwo half sections 60 and 61, the fomier being suitably mounted on themachine frame and the latter secured by screws 62 to the section 60 soas to form a flat circular chamber 63 within the housing 59. In theaxial center of the circular casing there is formed a central bosshaving an opening through which the end of the registration shaft 46projects. Movable within the space on chamber 63 is a switch member 64which is secured to the shaft 46 to be rotated therewith. The member 64is arranged to be rotated within the chamber 63, and is provided with acircular magnet 65 that scribes a circular path of movement 66 aroundthe axis of the shaft 46 during rotation thereof.

Formed integral with the supporting section 60 is a casing 66a having areed switch 67 mounted therein with a hermetical seal. The switch 67 ispositioned close to the flat wall of the section 60 in close proximityto the interior surface of the chamber 63. The switching elements 68 ofthe switch 67 have their actuating ends positioned in the circular pathof movement of the magnet 65 so that for each revolution of the magnetabout the axis of the shaft 46, the switch 67 will be actuated from oneof its controlling conditions to the other. It will be noted that thelongitudinal axes of the switch elements 68 are positioned along a chordof the longitudinal axes ane the path of movement 66 thereby asdistinguished from a perpendicular relationship if the elements 68 weremounted radially. By having this acute angular relationship, more of thereed switch elements are under the influence of the magnet 65, and theremay be a greater extreme of misalignment of the parts or tolerancesbefore adversely affecting precise operation of switching mechanisms.

In order to provide an adjusting means for th switch 67 relative to theangular orientation of the registration fingers 45 soas to insure properresetting of the machine control pulse count, the casing 59 may bebodily moved, within narrow limits. Such movement may be necessary inorder to arrange the switch elements 68 for actuation at a preciselocation relative to the magnet 65 the position of which, in turn, isindicative of the angular orientation of the fingers 45. The adjustingmeans comprises a fixed, block 69 mounted on the machine frame Fadjacent the casing section 66a, and a follower 70 movably retainedwithin the block 69. The follower 70 projects toward the section 60 andis received within a depression 71 formed in this section. Upon verticalmovement of the follower 70, as viewed in FIG. 6, in either direction,the casing 59 will be accordingly rotated slightly, as viewed in FIG. 5.In order to impart vertical movement to the follower 70, the block 69 isprovided with an adjusting screw 72 for forcing the follower in adownward direction, and an adjusting screw 73 for forcing the followerupwardly. For insuring precise positioning of the casing 59 andconsequently, the switch 67, an indicating means, in

the form of a pointer 74 secured to the machine frame and indicia 74ascribed on the section 60, is provided. FIGS. 7, 8 and 9 illustrate thecooperative operation of the registration fingers 45, the leading edgeof each sheet of paper being registered and fed to the printing machine,and the pinch rollers-50, 51. In FIG. 7, the sheet S, being supplied byeither of the sheet supplies 20 or 21 arrives just as the fingers 45move from its dotted position toward the full line position duringrotation of the fingersby'the shaft 46. Actually, the sheet may lagslightly in arriving at its illustrated position. At this time, thefingers are moving, in the direction of the arrow, at a speed slightlyless than that .of the leading edge of the sheet. Rotation of thefingers 45 is accomplished by the constant speed drive motor 30 by wayof the drive belt 48 and the variable speed device 47. The device 47, aswill be described hereinafter, is adapted to impart to the fingers,rotative speeds which are relatively, fast during most of a revolutionand slower during other portions of a revolution, and at an increasingspeed during sheet registration. During this portion of a revolution,when a sheet is registered on the fly, the sheet will be fed to theregistration station at a higher speed than when it is fed to theprocessing stationsby the pinch rollers 50, 51.

In FIG. 8, the sheet is shown against or going against the fingers andis registered thereby so that the leading edge is free of any skewbefore entering the processing stations of the machine. The rotativespeed of the fingers continues to increase until they reach the fullline position shown in FIG. 9. At this instant the fingers are moving ata speed equal to the machine processing speed so that the sheet will bepicked up by the pinch rollers 50, 51 for further movement through themachine. After the leading edge of the sheet has been picked up-by thepinch rollers, which are running at process speed,tl'1e fingersexperience a relative fast speed, attainingits maximum speed at aboutthe position shown in dotted lines in FIG. 9. In leaving the leadingedge of the sheet in FIG. 9, the fingers 45 must arrive at the positionshown in dotted lines in FIG. 7, which is indicative of its slowestspeed during a complete revolution, in time to catch the next followingsheet. If there is to be precise sheet feed through the processingstations of the machine, each sheet must be precisely spaced one fromanother as occurs as a result of the registration mechanism hereindescribed. Assuming that thespacing between sheets for very high speedmachine operation is to-be approximately 1 and 7% inches, it will beapparent that the fingers must move very swiftly through; that portionof their revolution when returning from the position shown in FIG. 9 tothe position shown in FIG. 7 in order to assure this spacing.

For typical speed relationships for sheet feeding, registration andmachine processing, the mechanism so far described is adapted asfollows: Assuming the machine processing speed is 20 inches per second;that is, each sheet must be introduced to the transfer nip C at thisspeed and all other processing stations are functioning approximately atthis speed, it is desirable that the sheet supply speed be greater inorder to insure time for proper registration and to speed up totalmachine operation. Greater sheet supplyspeed also 'minimizesthe effectof inefficiencie's or mis-timing in the sheet supplying devices 20, 21.Preferably, the sheet supply feed is approximately 30 inches per second.Under these circumstances, the fingers 45 must slow each sheet from aspeed of 30 inches per second to a speed of 20 inches per second inmoving through the positions shown in FIGS. 7, 8 and 9.'In accomplishingthese actions, the fingers as shown in full lines in FIG. 9 are at aneffective speed such that the sheet travels at20 inches per second atthe instant when sheet registration occurs, am the reset switch 67 hasbeen actuated. Actually, the speed of the fingers increases slightly inmoving from the positions of FIG."7 to FIG. 9, attaining the'processspeed at sheet registration. After this occurs,.faster increases infinger rotative speed are imparted to the fingers sothat at their dottedline positions in FIG; 9, their speed may approximate 40 inches persecond, the maximum so attained. After this, the speed may graduallylessen until the dotted position of FIG. 7 is reached wherein the speedmay be approximately l8 inches per second, a speed lower than processspeed and the minimum for any one complete rotation of the fingers.After leaving the dotted position of FIG. 7, the fingers will be inposition to intercept the leading edge of sheet- With the sheets beingmoved to the registration zone, defined by the dotted position of thefingers in FIG. 7, to the full line position of FIG. 9, at a greaterspeed than process speed, it will be apparent that after the fingershave moved from the dotted line position of FIG. 7, ahead of an oncomingsheet, they will be eventually contacted by the sheets leading edge asthey move from the FIG. 7 position to the FIG. 9 position. This contactmay occur any time during this travel, depending upon the-efficiency ofthe sheet supplies and their respective conveying means. It will beappreciated that this arrangement permits the precise registration ofeach sheet and the precise positioning thereof in the machine processingsystem for a fairly wide range of inaccurately timed sheet feeding tothe registration zone. The defined registration zone then is aregistration window having a width in which registration can take place.This window corresponds to approximately 90 of rotation of the fingersand allows a relatively wide margin of error in positioning of sheets ofpaper by the individual sheet supplies. During this travel of a sheetthrough the registration zone, it is only necessary that it be incontact with the fingers at the time registration is to be effected.

During movement of each sheet through the registration zone, regardlessof when the leading edge contacts the fingers, the speed of the sheetwill be slower from its entry speed of 30 inches per second to somethingless than the process speed of inches per second and then stabilized atthe process speed at registration. While at the slower speeds, thesheets will continue to experience a feeding force produced by either ofthe transport conveyors 40 or 42. During this time, the belts of thetransport will slip relative to the adjacent surfaces of the sheets.

In the above description-of the speed relationships, various speeds wererecited in order to emphasize or illustrate the relationships. Thespeeds so assigned to this description are only illustrative and needbear no resemblance in fact. What is important are the relationships ofthe speeds of the moving elements in the descriptions.

As previously stated, the registration fingers 45 rotate with theirshaft 46 at variable speeds, and this motion is imparted by way of thevariable speed device 47. This device includes an inner cylindricalelement 75 which is in the form of a pulley to which th belt 56 isapplied for effecting rotation of the pinch rollers 50, 51. Mounted onand exteriorly of the element and concentric therewith, is a circularmember 76 which is also in the form of a pulley. The drive belt 48 isapplied to this member for imparting, eventually, rotation to theregistration fingers 45. The pulley member 76 is rotatably related toand held upon the cylindrical element 75 by a retaining ring 77 on oneside and by a flange 78, formed on the element, at the other end. Aflexible ring-type clutch element 80 retained between cooperatingsurfaces of the element 75 and member 76 serves as a clutch therefor.Rotation of the pulley member 76 in one direction will impart rotationto the pulley element 75 in the same direction, but rotation of thepulley member 76 in the reverse direction will have no effect upon thepulley element 75.

The element 75 and therefore the member 76 and clutch element 80 aresupported upon a cylindrical retaining block 81 which is formed at oneend with a flange 82 arranged to be secured against movement to themachine frame. Surrounding the peripheral surface of the cylindricalblock is a circular needle bearing 83 held in place by the flange 82 anddetachable circular plate 84. The inner surface of the element 80 isforce fitted to the bearing 83 and in this way the structure 75, 76 and80 is mounted for rotation upon the fixed block 81.

The block 81 is formed with a through opening 85 having its axiseccentric relative to the axis of the block. The registration shaft 46projects through this opening and has its axis also eccentric relativeto the block 81. At the end of the shaft 46 which terminates within thecylindrical member 76 there is detachably secured an actuator arm 86 soas to be rotatable therewith. The arm 86 is formed with a slot 87 havingits longitudinal axis normal to the axis of the shaft 46 so as to beable to define a path of revolutiomA drive pin 88, formed on the innercylindrical surface of the element extends into the slot 87 and isadapted to travel reciprocably therealong. The parts so far describedare arranged so that the pulley element 75 and the pulley member 76 havetheir axes of rotation, designated by the numeral 90, coincident withthe axis of the block 81 and eccentric relative to the axis of the shaft46. During driving rotation of the pulley member 76, the pulley element75 is driven therewith thereby causing revolving of the drive pin 88about the axis 90. As the drive pin revolves, it imparts rotation to thearm 86 which in turn, imparts rotation to the shaft 46. Continuousrevolving action by the pin 88 at constant speed, and its cooperatingreciprocating movement relative to the slot 87, will impart variablespeeds of rotation to the registration fingers 45.

In FIGS. 7, 8 and 9, the drive pin 88, the actuating arm 86, the slot87, the axis 90, and the shaft 46 are shown in their relative positionsfor imposing the variable rotative motion upon the registration fingers.In FIG. 7, the revolving path of movement 100 for the pin 88 is shown asconcentric to the axis and eccentric relative to the axis of the shaft46. In the dotted position of the arm 86, the rotative speed thereof isslowest and the pin 88 is on one side of the axis 90 or diametricallyopposed relative to the axis of the shaft 46. As the pin movesdownwardly from this position, the rotational speed of the fingersincreases since the pin is moved out of its diametrically opposedrelationship and toward a position which is on the same side of the axis90 as the shaft. In FIG. 8, this repositioning is shown in progress andin FIG. 9, completed. The dotted position of the arm 86 in FIG. 9 isindicative of the highest rotative velocity attained by the registrationfingers since the pin 88 and the axis of the shaft 46 are along the sameradial line from the axis 90. In approaching this alignment, therotative speed of the fingers continue to increase as the positioning ofthe arm 86 in full line attests.

While the rotational velocity of the fingers 45 varies, as describedabove, the effect of the variation upon a sheet of paper beingregistered will be modified somewhat. In moving through the registrationwindow, that is, from FIG. 7 to FIG. 9, the effective radius of thefingers 45 relative to the leading edge of a sheet S will also vary.This variation is slight, however, and for that range, its effects willbalance out. In moving from the position of FIG. 8 to that of FIG. 9,the critical portion of the window, the rotative velocity of the fingersincreases slightly. This slight increase however is factored into thespeed relationship of the fingers as they rotate and does not of itselfaffect sheet speeds.

In order to extend the effectiveness of the window width, that is,provide more width-to-paper-travel, or conversely, lesspaper-travel-to-width ratio, the fingers are formed with curved surfaces101 which extend back toward the sheet supplies, to be contacted atdifferent points thereon by each sheet being registered as they travelthrough the window. For the illustrated configuration, and for the fullwindow width, distance of movement of the sheet is 10 percent less thanthe movement of the fingers. Thus, registration and accurate sheetpositioning relative to pitch reset can be accomplished in a shorteneddistance of paper travel than what would normally be required toaccomplish these functions. Or, to put it another way, a longer sheettravel is available for insuring these functions than what wouldnormally be effected if the curved surface 101 were not utilized on thefingers. The surfaces 101 are also arranged so that the leading edge ofeach sheet will orient as near as possible perpendicular to the surfaceand not slide off the surface during travel through the registrationzone. At the instant a sheet is registered and at the nip of the rollers50, 51, the surfaces 101 are exactly normal to the plane of the sheet.

The reset switch 67 is in circuit with the pulse counter 37 which may bepart of the machine logic LE, and actuation of the switch will initiatepulse recounting until subsequent actuation, in turn, producecorresponding re-counting. In this manner, pitch reset is accomplishedoff the registration mechanism and is utilized as the starting point, atleast countwise, for mechine control, processing and sheet monitoring.

The logic'equipment LE is operatively connected to the pulse generator36, the counting mechanism 37, clutches (not shown) for the paper sheetsupplies 20,21, the illumination lamps L to the corotrons 13, 27, themotor for the brush 28, the fuser 24 and the developing apparatus 17,and arranged so that these devices are functionally activated andcontrolled by a different counted number of the pulses in time sequence.Since the photoreceptor belt 12 is continuously being exposed byflashing imaging rays, the belt may contain a number of electrostaticimages, for example, five or more images between the exposure andtransfer stations. Similarly, the paper path between the paper suppliesand the transfer station C may contain two or three sheets. Anyparticular time cycle made operative by the timing arrangement may thenproduce sequential operation of the above-mentioned devices in an orderwhich affects different images, transfer operations and sheets of paper.In other words, the programming control system will maintain timingcontrol for five or more pitches concurrently processwise. For instance,after the machine has been turned On and the drive means 30 is in fulldrive operation so that control pulses are being produced, counted andreset by the reset switch 67, and the registration fingers are rotating,poised for the expectant sheets, the lamps L may be energized as thefirst event when the machine is placed in print condition. It will benoted that upon initial machine use, a sheet S will not have beenseparated from one of its supply stacks before the first flash of anoriginal D is made. In fact, there may be experienced two or three imageexposures on the belt 12 before the first sheet is separated from astack by one of the control pulses in the control signal. The first of aseries of produced latent images may be in or nearing the developingzone, and as images are so produced, the first one, now developed, isadjacent the transfer station in timed relationship to a sheet beingregistered. The short distance yet to travel after the registrationfingers 45 leave the sheet is factored into the pitch distance belt 12travels so that the developed image and the exact positioning it is tooccupy on the sheet will be in precise registration at transfer. Duringthe actuation of these process devices, other devices may be activatedto continue the processing of reproductions. For example, all thecorotrons would have been energized as well as the paper jam detectiondevices (not shown) located along the paper path of movement may besensed in sequence for the different sheets of paper in the path inorder to insure the proper positioning of the sheets. The fuserapparatus would have been energized before the first sheet arrived thereand successive energization of the cleaning and discharging elementsalso would have occurred. Upon release of the sheet of paper from thenip at station C, the cycle begins again and will produce the identicalseries of operations as discussed above.

While the invention has been described with reference to the structuredisclosed, it is not confined to the details set forth but is intendedto cover such modifications or changes as may come within the scope ofthe following claims.

What is claimed is:

1. An electrostatic printing apparatus for reproducing copies of anoriginal having a movable photoreceptor member including,

means for producing electrostatic latent images on said member,development means for applying developing material to each of the latentimages to develop the same,

transfer station adjacent the moving photo-receptor member at which eachdeveloped image is transferred, means for feeding copy material from asupply thereof to said transfer station for transfer of the developedimage to the copy material,

programming means associated with said image producing means and saidcopy material feeding means and operative when activated for controllingactuation of the feeding means in timed sequence relative to theproduction of each latent image by said image producing means, saidprogramming means including means for effecting the activation thereofonce in each of predetermined time cycles, and

means cooperatively associated with the movement of copy material tosaid transfer station for resetting said time cycle.

2. An electrostatic printing apparatus for reproducing copies of anoriginal having a movable photoreceptor member including,

means for producing electrostatic latent images on said member,

development means for applying developing material to each of the latentimages to develop the same, transfer station adjacent the moving belt atwhich each developed image is transferred,

means for feeding copy material from a supply thereof to said transferstation,

means for generating in cycles series of control pulses, said generatingmeans including means associated with said image producing means andsaid copy material feeding means for controling actuation of the feedingmeans in timed sequence rela- 4. An electrostatic printing apparatus forreproducing copies of an original having a movable-photoreceptor memberincluding,

means for producing electrostatic latent images on said member,

development means for applying developing material to each of the latentimages to develop the same, transfer station adjacent the moving belt atwhich each developed image is transferred,

means for feeding seriatim sheets of copy material from a supply thereofand to said transfer station at the rate of one sheet per actuationthereof for transfer of the developed image thereto,

means for generating in cycles series of control pulses, said generatingmeans including means associated with said image producing means andsaid sheet feeding means for controlling actuation of said sheet feedingmeans in timed sequence relative the production of each latent image bysaid image producing means for each of said cycles, and

a sheet sensing device adjacent said sheet feeding means for sensingeach sheet of material as the same moves toward the transfer station,said generating means being operatively connected to said sensing devicefor effecting the start ofeach series of control pulses for each sheetof material sensed.

5. An electrostatic printing apparatus for reproducing copies of anoriginal having a movable photoreceptor member including,

means for producing electrostatic latent images on said member,

development means for applying developing material to each of the-latentimages to develop the same, transfer station adjacent the moving belt atwhich each developed image is transferred,

means for feeding seriatim sheets of copy material from a supply thereofand to said transfer station at the rate of one sheet per actuationthereof for transfer of the developed image thereto,

means for generating in cycles series of control pulses, said generatingmeans including means associated with said image producing means andsaid sheet feeding means for controlling actuation of the sheet feedingmeans in timed sequence relative to the production of each latent imageby said image producing means for each of said cycles, and

a registration device adjacent said sheet feeding means for contactingand registering each sheet of material as the same moves toward thetransfer station, said generating means being operatively connected tosaid registration device for effecting the start of each series ofcontrol pulses for each sheet of material registered.

6. An electrostatic printing apparatus for reproducing copies of anoriginal having a movable photoreceptor member including,

means for producing electrostatic latent images on said member, 4

development means for applying developing material to each of the latentimages to develop the same,

a transfer station adjacent the moving belt at which each developedimage is transferred,

means for feeding seriatim sheets of copy material from a supply thereofand to said transfer station at the rate of one sheet per actuationthereof for transfer of the developed image thereto,

means for generating in cycles series of control pulses, said generatingmeans including means associated with said image producing means forcontrolling action of the same at the rate of one image producingoperation in each series of generated pulses, and

means responsive to the movement of each sheet of copy material forresettingeach of said time cycles.

7. An electrostatic printing apparatus for reproducing copies of anoriginal having a movable photoreceptor member including,

means for producing electrostatic latent images on said member,

development means for applying developing material to each of the latentimages to develop the same,

a transfer station adjacent the moving belt at which each developedimage is transferred,

means for feeding seriatim sheets of copy material from a supply thereofand to said transfer station at the rate of one sheet per actuationthereof for transfer of the developed image thereto,

programming means associated with said image producing means and saidsheet feeding means and operative when activated for controllingactuation of said sheet feeding means in timed sequence relative to theproduction of each latent image by said image producing means, saidprogramming means including means for effecting the activation thereofonce in each of predetermined time cycles, and

means responsive to the movement of each sheet of copy material forresetting said time cycle.

8. An electrostatic printing apparatus for reproducing copies of anoriginal having a movable photoreceptor member and a plurality ofprocessing devices arranged when activated for producing electrostaticlatent images on the photoreceptor member for developing the images, forfeeding sheet material seriatim, and for transferring developed imagesto the moving sheet material, and drive means operatively connected tothe photoreceptor member for driving the same in the endless path, theimprovement comprising,

means for generating a train of control pulses for control activation ofat least one of the processing devices, and

means responsive to the feeding of sheet material for converting thetrain of control pulses into series of pulses at the rate of one seriesfor each sheet of material fed.

1. An electrostatic printing apparatus for reproducing copies of anoriginal having a movable photoreceptor member including, means forproducing electrostatic latent images on said member, development meansfor applying developing material to each of the latent images to developthe same, transfer station adjacent the moving photo-receptor member atwhich each developed image is transferred, means for feeding copymaterial from a supply thereof to said transfer station for transfer ofthe developed image to the copy material, programming means associatedwith said image producing means and said copy material feeding means andoperative when activated for controlling actuation of the feeding meansin timed sequence relative to the production of each latent image bysaid image producing means, said programming means including means foreffecting the activation thereof once in each of predetermined timecycles, and means cooperatively associated with the movement of copymaterial to said transfer station for resetting said time cycle.
 2. Anelectrostatic printing apparatus for reproducing copies of an originalhaving a movable photoreceptor member including, means for producingelectrostatic latent images on said member, development means forapplying developing material to each of the latent images to develop thesame, transfer station adjacent the moving belt at which each developedimage is transferred, means for feeding copy material from a supplythereof to said transfer station, means for generating in cycles seriesof control pulses, said generating means including means associated withsaid image producing means and said copy material feeding means forcontroling actuation of the feeding means in timed sequence relative tothe production of each latent image by said image producing means foreach of said cycles, and means cooperatively associated with themovement of copy material to said transfer station for resetting each ofsaid cycles.
 3. The apparatus of claim 2 wherein said generating meansis a timing device.
 4. An electrostatic printing apparatus forreproducing copies of an original having a movable photoreceptor memberincluding, means for producing electrostatic latent images on saidmember, development means for applying developing material to each ofthe latent images to develop the same, transfer station adjacent themoving belt at which each developed image is transferred, means forfeeding seriatim sheets of copy material from a supply thereof and tosaid transfer station at the rate of one sheet per actuation thereof fortransfer of the developed image thereto, means for generating in cyclesseries of control pulses, said generating means including meansassociated with said image producing means and said sheet feeding meansfor controlling actuation of said sheet feeding means in timed sequencerelative the production of each lAtent image by said image producingmeans for each of said cycles, and a sheet sensing device adjacent saidsheet feeding means for sensing each sheet of material as the same movestoward the transfer station, said generating means being operativelyconnected to said sensing device for effecting the start of each seriesof control pulses for each sheet of material sensed.
 5. An electrostaticprinting apparatus for reproducing copies of an original having amovable photoreceptor member including, means for producingelectrostatic latent images on said member, development means forapplying developing material to each of the latent images to develop thesame, transfer station adjacent the moving belt at which each developedimage is transferred, means for feeding seriatim sheets of copy materialfrom a supply thereof and to said transfer station at the rate of onesheet per actuation thereof for transfer of the developed image thereto,means for generating in cycles series of control pulses, said generatingmeans including means associated with said image producing means andsaid sheet feeding means for controlling actuation of the sheet feedingmeans in timed sequence relative to the production of each latent imageby said image producing means for each of said cycles, and aregistration device adjacent said sheet feeding means for contacting andregistering each sheet of material as the same moves toward the transferstation, said generating means being operatively connected to saidregistration device for effecting the start of each series of controlpulses for each sheet of material registered.
 6. An electrostaticprinting apparatus for reproducing copies of an original having amovable photoreceptor member including, means for producingelectrostatic latent images on said member, development means forapplying developing material to each of the latent images to develop thesame, a transfer station adjacent the moving belt at which eachdeveloped image is transferred, means for feeding seriatim sheets ofcopy material from a supply thereof and to said transfer station at therate of one sheet per actuation thereof for transfer of the developedimage thereto, means for generating in cycles series of control pulses,said generating means including means associated with said imageproducing means for controlling action of the same at the rate of oneimage producing operation in each series of generated pulses, and meansresponsive to the movement of each sheet of copy material for resettingeach of said time cycles.
 7. An electrostatic printing apparatus forreproducing copies of an original having a movable photoreceptor memberincluding, means for producing electrostatic latent images on saidmember, development means for applying developing material to each ofthe latent images to develop the same, a transfer station adjacent themoving belt at which each developed image is transferred, means forfeeding seriatim sheets of copy material from a supply thereof and tosaid transfer station at the rate of one sheet per actuation thereof fortransfer of the developed image thereto, programming means associatedwith said image producing means and said sheet feeding means andoperative when activated for controlling actuation of said sheet feedingmeans in timed sequence relative to the production of each latent imageby said image producing means, said programming means including meansfor effecting the activation thereof once in each of predetermined timecycles, and means responsive to the movement of each sheet of copymaterial for resetting said time cycle.
 8. An electrostatic printingapparatus for reproducing copies of an original having a movablephotoreceptor member and a plurality of processing devices arranged whenactivated for producing electrostatic latent images on the photoreceptormember for developing the images, for feeding sheet material seriatim,And for transferring developed images to the moving sheet material, anddrive means operatively connected to the photoreceptor member fordriving the same in the endless path, the improvement comprising, meansfor generating a train of control pulses for control activation of atleast one of the processing devices, and means responsive to the feedingof sheet material for converting the train of control pulses into seriesof pulses at the rate of one series for each sheet of material fed.